Recognizing and Treating Midcarpal Instability

Abstract

Since midcarpal instability was originally described in 1981, much has been learned about this clinical entity. Although relatively uncommon, mid-carpal instability is becoming increasingly recognized as our level of knowledge and awareness increases. The pathophysiology is thought to be caused by congenital laxity, gradual attenuation, or traumatic disruption of key carpal ligaments, which leads to a hypermobility of the intercalated proximal row segment and a “catch-up clunk” as the patient brings his or her wrist into ulnar deviation. Patients primarily complain of painful clunking with ulnar deviation activities. The midcarpal shift test is the premier clinical diagnostic test for identifying a patient with midcarpal instability, and reproduction of the painful clunk with this test is considered positive for the disorder. Most patients with midcarpal instability respond to conservative measures that include anti-inflammatories, avoidance of aggravating activities, special splints, and physical therapy. If these measures fail, limited intercarpal arthrodesis or dorsal capsulodesis are described surgical techniques for eliminating the painful clunk in this disorder.